Washington (CNN) – The drawdown of U.S. forces in Iraq remains on track, and the military will meet the troop level benchmark laid out by President Obama, according to the Army Chief of Staff.

In an interview with CNN Chief National Correspondent John King, Gen. George Casey said the military is slated to reduce troop levels to 50,000 by the end of August.

"[I]t's something we've been working on with the leadership in Iraq for more than 18 months. We have been gradually moving the extra equipment and things out. There's a great plan in place and we're executing that plan right now," Casey said on CNN's John King, USA.

The U.S. now has more troops in Afghanistan than Iraq for the first time since 2003.

When asked about the need for additional resources in Afghanistan - beyond the 30,000 additional troops scheduled to be deployed there - Casey said the number should be sufficient.

"I've heard no discussion of additional troops beyond the 30,000. We, the chiefs, looked at that and General [Stanley] McChrystal has looked at that and we all believe that that will be sufficient for him to accomplish him mission."